Process for producing a die
A method of making an impression die comprises the steps of providing a substantially planar bendable bimetal plate 10 consisting of copper and steel bonded together, forming a relief pattern 14 in the surface of the copper for example by an etching process, forming the plate into a non-planar sleeve with the copper on the outside and joining the free edges of the sleeve together. Preferably the free edges of the sleeve 10 are joined together while the sleeve is mounted on a metal mandrel 15.
1. A method of making an impression die for use in an embossing, hot foiling, or hot stamping process, the method comprising the steps of:
providing a single substantially planar bendable bimetal plate having a non-ferrous metal layer and a steel layer bonded together,
wherein said bimetal plate includes leading and trailing edges;
forming a relief pattern in the surface of the non-ferrous metal layer by an etching process;
removing substantially all of the non-ferrous metal layer along at least a portion of each of the leading and trailing edges of the plate to expose the steel layer at said leading and trailing edges to secure the edges together;
forming the plate into a single non-planar sleeve with the non-ferrous metal layer on the outside; and
securing the leading and trailing edges of the plate together along at least a portion of the exposed steel layer so as to form a single continuous sleeve.
2. A method according to claim 1 , wherein the sleeve is generally cylindrical.
3. A method according to claim 1 , wherein there is no intervening layer between the non-ferrous metal and steel layers.
4. A method according to claim 3 , wherein the non-ferrous metal and steel layers are bonded together via cladding.
5. A method according to claim 1 , wherein the thickness of the plate is in the range 0.5 to 1.5 mm.
6. A method according to claim 1 , wherein the thickness of the steel layer is from 0.2 mm to 0.4 mm.
7. A method according to claim 1 , wherein the thickness of the steel layer is substantially 0.2 mm.
8. A method according to claim 1 , wherein the leading and trailing edges of the plate are joined together by welding.
9. A method according to claim 8 , wherein the leading and trailing edges of the plate are joined together by spot welding.
10. A method according to claim 1 , wherein the relief pattern in the surface of the non-ferrous metal layer is produced by a deep etching process.
11. A method according to claim 1 , wherein the non-ferrous metal layer comprises copper.
12. A method according to claim 1 , wherein the leading and trailing edges of the sleeve are secured together while the sleeve is mounted on a metal mandrel.
13. A method according to claim 12 , wherein the sleeve extends substantially entirely across the width of the mandrel.
14. A method according to claim 12 , wherein the sleeve extends only partially across the width of the mandrel.
15. A method according to claim 12 , wherein when the metal mandrel is heated, it expands so that the sleeve fits closely upon it.
16. A method according to claim 1 , wherein the leading and trailing edges of the plate are overlapped prior to being secured together.
17. A method according to claim 1 , wherein the leading and trailing edges of the plate are secured together via butt-welding.
18. A method according to claim 1 , wherein the non-ferrous metal layer is removed for a width of about 5 mm along the leading and trailing edges of the plate to expose the steel layer.